Definitive Technology Symphony 1 Over-Ear Bluetooth Wireless Headphones - Black Immerse yourself in precision-crafted, audiophile-grade sound wherever you are with the Definitive Technology Symphony 1 executive Bluetooth headphones. Connectivity Technology: Wireless 50mm drivers offer detailed, full-fidelity highs and mids-and rich, deep bass-for a big, natural soundstage Convenient Bluetooth connectivity for wireless listening and phone calls Closed back, over-ear design seals out external sound while active noise cancellation (ANC) technology dramatically reduces ambient noise Built-in rechargeable battery lasts up to 15 hours with noise cancellation on